"He's the player we're going to look to, especially during the tough times - that's what makes him such a great leader.
"Having him there is going to be a big boost for us."
Gallen was originally placed on a restricted training regime due to the knee injury which ruled him out of Cronulla's NRL win over the Storm last weekend, but strained his thigh as he worked his way back to fitness.
He was so concerned about the injury's effect on his teammates he addressed the squad on Friday to reveal the extent of his concerns.
Farah claimed Gallen's absence from the earlier session would have minimal impact on the side's preparations for Wednesday night.
"Gal's the sort of player who you don't need training every day, he's been there and he knows what it's all about," Farah said.
"There's been a bit of speculation about it but within camp we've always been confident he'd be right.
"He talked to us because he's been a bit down and he was a bit worried about it earlier in the week and maybe let it affect him.
"He just assured us that he'd be right and that he was going to try and be a bit more positive.
"It's pretty tough with those sorts of injuries, sometimes it does get to you and you start to worry, especially with such a big game coming up."
Gallen's recovery offset any concerns over the unavailability of 18th man Tariq Sims, who suffered a broken leg in North Queensland's win over Penrith on Saturday night.
The Blues already have Wests Tigers prop Aaron Woods in camp as cover for any late mishap.
- AAP